Self -Fertilization Induced by Artificial Means. 177 



the spermatozoa of one individual must be supposed to be male, 

 and in another individual the reverse; but certainly this is not the 

 case, and could not have been Castle's meaning, for if it were so 

 then half of the individuals would be infertile with the sperm of 

 the other half, and this is not so. I have pointed out that 

 my results with ether, etc., do not support Castle's assumption, 

 although it might, of course, be claimed that the ether causes 

 the spermatozoa to lose, as it were, their homosexual repugnance. 

 However this may be, I have found that no such lack of power 

 to self-fertilize is found in some other ascidians, as in Molgula 

 for example. If my supposition is correct, that self-fertilization 

 in Ciona is due to the presence in the eggs of some substance that 

 brings the spermatozoa to rest, the whole question assumes a very 

 different aspect and does not appear to have any connection with 

 the question of the determination of sex. 



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